Magenta (2014)

publisher blurb

"MAGENTA, OPEN SOURCE MILITARY ROLE-PLAYING is designed from the ground up for roleplay in the social context of military culture and the explosive violence of modern war.

The Magenta engine was first used in Sanguine's critically-acclaimed RPG ALBEDO: Platinum Catalyst, and now it sees new life as open-source, Open Gaming Licence content. The document only contains the rules, and has no setting information.

Realistic combat rules, without action-movie exuberance. Status-based injury and morale keeps the accounting of combat simple and quick.
Chain of command, where players control both one Main Character and a retinue of Supporting Characters, so realistically (and mercilessly) dangerous combat won't knock players out of the game.
Morale, as characters succumb not only to wounds, but to the shock and awe of deadly combat. Keep your Supporting Characters alive through multiple missions, and their morale grows along with their loyalty.
Firearm statistics are modeled on real-world physics and data, yet gunplay is quick and easy in practice.
Support rules include artillery and air support, remote-controlled drones, and targeting by remote camera, so it scales easily in to the near future and far future.
Open Source under the Open Gaming License, for use in your own games and publications."